Base block for crucibles or the like



Nov. 14, 1944.

G. T? HUBBELL Filed Dec. 10, 1942 BASE BLOCK FOR CRUCIBLES OR THE LIKEPatented Nov. .14, 1944 BASEBLOCK Foe CRUCIBLES-OR THE-LIKE f George-T.Hubbell, West Haven, Conn, assignor UNITED sTArE to American CrucibleCompany, Shelton, Conn a corporation of Delaware i ApplicationD ecember10; 1942, Serial No; 468,533

w 4 Claims.

This'inventionrelates to base blocks for. crucibles, and moreparticularly to a supporting device for a crucible to support the latterWithin a furnace so that it will be efficiently and evenly willbepermitted toenterthe spaces betweenthe supporting members andattackdirectlythe bott'omof the crucible.

Still another object of the invention is the heated, particularly overthe bottom portion 5 provision of afbasev block for crucibles providedthereof, while at the same time the flame of the with a solid baseportion and. a pluralityof upburner will not be permitted to contact thebotstanding supp r n mem r t r such that tom of the crucible directly.when a crucible is supported on the supporting crucibles employed infoundry work are commembers the furnace flame Will not enter the posedof a material which may be approximately s e between the supporting m rwh fifty percent graphite and the remainder silicon e flame is pp to thefurnace in one i carbide and clay. Usually the side walls. of the t o ul tend to Cause the flame to enter crucible are glazed with aflame-resisting mathespaces tw n the ppor i g member wh n terial, butthe-bottom i'sl'eft unglazed. For this the base block is inverted andthe crucible is reason it is not desirablethat the flame contactSupported u n h as p t nv f t e blockthebottom of the crucible directly,or-the graphite these a other e the invention 00 will b oxidized, isists in thenovel features and "combinations of It is,however, desirablethat thebottom of the parts hereinafter described a d a medcruciblebeevenly heated, andparticularly that i the accompanying drawing: itbeheated to the same extent .asthe side walls 1 i nal V e Of a furnaceand a so that unequal expansion and cracking ofthe crucible supported 9base block embodyingcrucible will not result. It has been proposedmy'ihvehtien; in the past to place the crucibles on supports 2 i aseetionelview On line of which have a solid top portion, thuspreventing- 'Fig-3-is a -P a View f the a e b c the flame fromcontacting the body of the cru- Fig-4 is a Side ew Of the block; andcible. ,Such a support :or base block, however, a Sectional V On f Fdoes not permit the hot gases from the flame to To illustrate a pre e eembodiment of y contact the bottom for the crucible, but ratherinvention, a sh wn in a conventional mantends to insulate thisportion ofthe crucible from e a u a 9 having a linin l l and a botthe heated gasesso that it does notreceive-as tom portion l2, which parts H and I2 willnormuchheat as theside walls. This not only does mally be e ofrefractory a eria The Wa l notlaccomplish effective melting of thematerial Ofihe lining ll maybe provided han openirig in the crucible,.but heats the latter unevenly 7 own in'dotted'lines in Fig. and y beith d i bl resume observed that this opening is obliquely formed oobject of the present invention is the prointhe wall of the crucible sothat the flame from vision of a base .block ior crucibles which'will hburner nozzle placed in h penin will' per itth hot. gases of th furnaceflame t directed substantially tangentiallyto the space contact directlywiththe bottom of the crucible, between the ace lining and the supp butat the same time will prevent the flame itblock, he l e he einafterdescribed. self fromcontacting thisportion of the crucible. 40 Withinthe u ace is disposed a crucible 14 Another obj ctof th i v nti .1 thproviwhich rests on -a base block I5, there being a sufiision of a baseblock for crucibles so formed that Ciehli annular Space remaining etweenthe side the bottom of the crucible will be subjected Wall of thefurnace and the crucible and block directly to the hot gases of theflame for efficient 11 which it will be n from g- 2, ti b t 111 t beubjected t t fl the opening 13 is directedsubstantiallytangenitself,thus preventing oxidation of the materialtielly o t b ock l5 so as'to direct the flame of whichthe cr cibl is de,around the block in the space between the lat- .Astillfurther objectof:theinvention is the ter and the furnace lining. I provisionoi a baseblock for crucibles comprising The baseblock l5 iS-made 0f ytea lowrbase' portion having. thereon a plurality rial so as to Withstand theheat of the flame, and of upstanding spaced supporting members socomprises abaseport ion [6, which, inthe form of formed that when theflame is applied to the my invention shown, is substantially circular inblock in one direction, forexarhple, azclockwiseshape,.anda..plurality-of upstanding supporting direction it willtendtopassaround the exterior 7 members I1, there being four of thesemembers, of.;.theblock,'whi1e;the. hot.gases..-from theflame, 56 asshownin the -drawing, although the exact number is not material. It will benoted that these members are spaced from each other both at the centerof the base block [6 and also between the side walls of the supportingmembers, as shown at I8, so as to permit the hot gases from the flame toenter the spaces l8 and circulate freely therethrough in direct contactwith the bottom of the crucible M.

The members I! are curved from their inner portions outwardly, andparticularly at their outer end portions, so that the flame entering thespace about the block through the opening I3 will tend to be directedabout the periphery of the block and restrained from entering the spacesl8, so that the flame will not come in contact with the bottom or baseof the crucible. As shown in Fig. 2 of the drawing, the flame isdirected in a clockwise direction, and correspondingly, as shown in Fig.3, the elements H are so shaped that when the flame tends to pass aroundthe base block in a clockwise direction it will continue in this pathand will not be deflected through the spaces Hi. If it is desired to usea similar block with a furnace in which the flame is directed in acounter-clockwise direction, the elements 11 would be reversed withrespect to their direction of curvature shown in Fig. 3.

While the exact shape of the member I! is not important in all aspectsof the invention, I have found that a very eflicient structure resultswhen both of the lateral surfaces of these elements are formed along thearcs of curves. For example, as shown in Fig. 3, the shorter wall ab ofone of the members Il may be formed on the arc of a curve having itscenter at c, which center is midway between the ends of a radius :r--.rof the base block [6. The radiu of the arc a--b which has been chosen isone half that of the radious of the block, so that if the curve a-b werecontinued it would pass through the center of the block, and also betangent to the periphery of the block. The longer wall of the member His formed of a similar curve d--e having its center at the point ,1 on aradius :cy 60 from the radius on which the point is located, this curvehaving the same radius as the curve w-b. However, from the point e thewall is continued to the point 9/, following the periphery of the baseportion Hi from the point e to the point 9. A suitable opening is leftbetween the inner ends of the members at the center at of the baseportion l6, and the ends of the members I! are rounded off, the curvesof the ends merging into the two curves of the side .walls, as explainedabove. This forms these supporting members of a substantially tear-dropshape, so that they will tend to cause the flame directed into the spacebetween them and the furnace wall to sweep around their outerperipheries instead of passing into the spaces between them. The facea-b of the next supporting member I! is formed about a center on aradius :r-z, which radius is at an angle 39 to the radius :ry, and thisprocess is continued about the block. Preferably the upstandingsupporting members I? are formed integrally with the base portionsthereof, although this is not imperative. It is, however, desirable tohave them secured to the base portion It so that they will always occupythe proper positions with respect to the block and with respect to' eachother to prevent the flame coming in contact with the bottom of thecrucible.

In some instances it is desired to have the crucible supported upon asolid base, but to provide for the flame, even if tangentially directed,to enter below this base so that the bottom of the crucible will beevenly heated and the base itself will prevent the flame from coming incontact with the bottom of the crucible. To eflect this result it ismerely necessary to turn the base block illustrated upside down withrespect to the position shown in the drawing herein. When the base blockis thus reversed, the crucible will rest upon the solid portion IE, andthe direction of the curvature of the supporting members I! will ineffect be reversed. That is, the outer ends of these members will pointin a direction opposite to that shown. As will be clearly seen from Fig.2, a flame entering through the opening 13 when the base block isinverted will tend to enter the spaces l8 between the member H, and thuspass directly below the base portion I6, heating it evenly and likewiseheating the bottom of the crucible evenly and efiiciently. Therefore,whether the 'particular operation which is to be carried out is bestserved by having the flame pass around the base block, or pass throughthe spaces below the block, either effect may be accomplished by usingthe device illustrated in upright or inverted position, while in eitherposition the bottom of the crucible is evenly heated and the flame isprevented from coming in direct contact therewith.

The base block will be made of a suitable refractory material towithstand the high temperature of the burner flame, and will usually bemade of a silicon carbide clay-bonded refractory material, although itsparticular composition is not of importance in all aspects of theinvention.

While I have shown and described a preferred embodiment of my invention,it is to be understood that it is not to be limited to all of thedetails shown, but is capable of modification and variation withinthespirit of the invention and within the scope of the claims.

What I claim is:

1. A base block for supporting crucibles or the like in the heatingchamber of a furnace, comprising a circular base portion havingupstanding spaced supporting members on one face thereof, each of saidmembers extending from a point adjacent the center of the base portionto a point adjacent the periphery thereof, and said members beingcorrespondingly curved adjacent their outer ends to direct a flamearound the outer ends of said members when said flame is directed aroundthe block in one direction and to cause the flame to enter the spacesbetween said members when the flame is directed around the block in theopposite direction, said block being adapted to rest freely on the floorof the heating chamber and being reversible in position to rest eitheron the base portion or on said members.

2. A furnace comprising a heating chamber having, adjacent the base, atangentially disposed burner inlet opening, a base block adapted tosupport a receptacle for the material to be heated, and resting freelyon the floor of the chamber and reversible top for bottom thereon, theperiphery of said block being spaced from the wall of the chamberopposite to said opening, said block comprising a base portion havingspaced upstanding receptacle supporting members thereon, and saidmembers extending from a, point adjacent the center of the block to theperiphery thereof and having their outer ends ,side wall convexly curvedand the opposite side curved in a direction to cause the flame to passaround said members when applied to the block in one direction and toenter the space between said members when applied to the block in theopposite direction.

3. A furnace comprising a heating chamber having, adjacent the base, atangentially disposed burner inlet opening, a base block adapted tosupport a receptacle for the material to be heated, and resting freelyon the'floor of the chamber and reversibletop for bottom thereon,

the periphery of said block being spaced from the wall of the chamber,opposite to said opening, said block comprising a base portion havingspaced upstanding receptacle supporting members thereon, said membersextending from a point adjacent the center of the block to' theperiphery thereof and having their outer ends curved ina direction tocause the flame to pass around said members when applied to the block 20in one direction and to enter the space between said members whenapplied to the block in the opposite direction, and said members havingone wall concavely curved.

4. A base block adapted to be inserted in and removed from a circularfurnace chamber having a substantially tangentially extending burnveropening, said base block being adapted to support a receptacle formaterial to be heated and substantially coaxial therewith, andcomprising a circular disc portion and a plurality of flanges on,oneface thereof, said flanges being spaced apart at the center of saidblock and along their lengths, the opposed surfaces of said flangesdefining passages with their outer ends facing substantiallytangentially of theblock, whereby.

when said block is inserted one side up in said furnace opposite to saidburner opening, the flame from said burner opening" will in part entersaid passages, and when said block is inserted the other side up,substantially all of the flame will tend to flow past the outer ends ofthe passages without entering the same.

GEORGE T. HUBBELL.

